Modular rail systems have many applications, from heavy duty industrial applications such as construction to light duty applications such as building toys for creating various constructs limited only by the imagination of a child.
How the rail units connect with one another, how quickly they fasten and unfasten, and how securely they fasten to one another distinguish light duty from heavy duty modular rail systems. It may be desirable to have a fastening apparatus for a modular rail system that can be scaled up or scaled down, depending upon the application. A modular rail system with an improved fastening apparatus may minimize the number of parts and the time required for connecting rail units. Such a modular rail system may permit fast, snap-action releasable connections that are reliable and secure.